Cross-symmetry breaking of two-component discrete dipolar matter-wave solitons

TL;DR

This paper investigates how the orientation of dipoles influences symmetry breaking in two-component discrete dipolar Bose-Einstein condensate solitons, revealing controllable phase transitions driven by dipole angles and interwell coupling.

Contribution

It introduces a novel analysis of cross-symmetry breaking in dipolar condensates with asymmetric cross-interactions due to dipole orientation, expanding understanding of phase transitions in such systems.

Findings

Cross-symmetry breaking can be controlled by dipole orientation and hopping rate.

Both sub- and super-critical symmetry breaking types are identified.

Dipole angle significantly affects soliton shape and phase transition characteristics.

Abstract

We study the spontaneous symmetry breaking of dipolar Bose--Einstein condensates trapped in stacks of two-well systems, which may be effectively built as one-dimensional trapping lattices sliced by a repelling laser sheet. If the potential wells are sufficiently deep, the system is modeled by coupled discrete Gross--Pitaevskii equations with nonlocal self- and cross-interaction terms representing dipole--dipole interactions. When the dipoles are not polarized perpendicular or parallel to the lattice, the cross-interaction is asymmetric, replacing the familiar symmetric two-component solitons with a new species of cross-symmetric or -asymmetric ones. The orientation of the dipole moments and the interwell hopping rate strongly affect the shapes of the discrete two-component solitons as well as the characteristics of the cross-symmetry breaking and the associated phase transition. The sub- and super-critical types of cross-symmetry breaking can be controlled by either the hopping rate between the components or the total norm of the solitons. The effect of the interplay between the contact nonlinearity and the dipole angle on the cross-symmetry breaking is also discussed.